A body at rest is acted upon by a constant force of 18 Newton and moves 72 m in 6 seconds what is the mass of the body
Answers
Explanation:
The mass of the body is m=2kg
The force applied on the body F=7N
The coefficient of kinetic friction =0.1
Since the body starts from rest, the initial velocity of body is zero.
Time at which the work is to be determined is t=10s
The acceleration produced in the body by the applied force is given by Newtons second law of motion as:
a′=mF=27=3.5m/s2
Frictional force is given as:
f=μg=0.1×2×9.8=1.96
The acceleration produced by the frictional force:
a"=−21.96=−0.98m/s2
Therefore, the total acceleration of the body:
a′+a"=3.5+(−0.98)=2.52m/s2
The distance traveled by the body is given by the equation of motion:
s=ut+21at2
=0+21×2.52×(10)2=126 m
(a) Work done by the applied force,
Wa=F⋅s=7×126=882 J
(b) Work done by the frictional force,
Wf=F⋅s=1.96×126=247 J
(c), (d)
From the first equation of motion, final velocity can be calculated as:
v=u+at
=0+2.52×10=25.2